Solex Carb Problems

I have a 1972 Opel Gt with a solex carb and its causing me troubles. The carb is CHUGGING gas. At the moment my gas tank is pulled out because i have to get the gas tank boiled but i have the line bypassed to a 1 gallon tank. But anyways the carb is chugging gas and when you give it alot of gas at one time it will sound like it will want to die then after about 3-4 seconds it will start to rev up the engine. What are the suggestions do you think its a vaccum leak or it just needs to be adjusted?

By chugging, do you mean that it floods with fuel? Flooding is when the carb pours fuel down the throats uncontrollably, and overloads the engine. If this is the case, the most probable cause is a stuck inlet valve. Remove the air-horn, and you will find it right behind the inlet pipe, at the underside of the air-horn. Remove it with a 15mm socket (if I remember correctly) and work it a bit (it only has a small moving rod) while spraying with carb cleaner from the inlet side... Most of the times this solves it...

To remove the air-horn, you have to disconnect the choke element complete with the coolant pipes(or just the cable if it is electric), and disconnect the fast idling adjusting rod (the threaded rod under the choke, that the choke lever is held on it by 2 nuts).

Absolutes.....

Okay guys..... lets just say that ALMOST everyony on this site MIGHT tell you to purchase a weber over the time and effort of bringing the solex back/near orginal performance levels.

The data that I have gotten from the internet, this site, and import car folks back in early 70's when I replaced my solex on my first GT said get a weber you will be pleased. They were right.... I have never gone back. But hey, I will back off and say to GT DRIVER, go with your solex as long as you can.............. and then STEP UP!!!

The best Solex repair guy/tuner I know is Bill Daley. He can make them run like a good TAG watch. I used to ship him Solex carbs left and right. For every 10 or so carbs, maybe 2-3 were 'good ones'. The carbs warp in multiple places, and once they warp, they are junk. No rebuild kits will bring them back to life at that point, they are beyond repairing correctly.

However, every once in a while there's a 'good' Solex that shows up (I've only had one original Solex that did this personally) that actually performs correctly. The only other Solex I've owned that worked perfectly was an NOS Solex I had years ago...wish I had kept it. Otto has one that works very well on his Kadett, which is probably why he is emphatic about you keeping yours (we all love you Otto, but Solex did not earn their reputation by chance!).

That said, it's genuinely easier to keep and maintain a Weber than a Solex. It is far more tuneable in terms of parts availability and general knowhow, and you'll get a boost in power to boot. The frustration levels are dramatically reduced when dealing with a Weber too.

About the specific problem you mentioned (when opening the throttle, the engine wants to die for a few seconds and then picks up). This sounds much like a faulty accelerator pump. With the air-cleaner removed and the engine not running see down the primary throat while manually operating the throttle linkage. Does the little brass tube inject fuel in the carb's primary throat? It should be a powerful column of fuel, solid and not aerated, which should be aimed between the throttle valve and the venturi wall towards the secondary barrel. If it does not inject fuel, the diaphragm is most likely torn. If it injects fuel, then check the aiming and correct if needed GENTLY with a pair of needle nose pliers (removing the air-horn will make adjustment MUCH easier).

About the low mileage now, what numbers do you get? Low mileage can be caused by several things, and also, possibly a combination of things. Is your engine in tune? That is:

If these are verified good, your brakes are not dragging and your clutch isn't slipping, then you can move to the carb for low mileage problems...

Check that your jetting is correct for your carburetor. In the downloads section there is a scanned version of the Factory Service Manual (FSM) available for downloading, in it you can find the correct size of jets that should be in your carburetor, and also the correct procedure to make all idle adjustments. The last (idle adjustments) is pretty important, because most of the driving we actually do is on the progression circuit (part of the idle circuit) and less on the main jet, which is most effective above 3000rpms.

In a small nutshell. Do the prophelactic trick on the vacuum secondary unit and replace your spacer for the intake valve with the same thickness and do the surfaces like you would an oil pump cover and use a good rebuild kit and your back in business. On this one I'm on Otto's side. Give it a chance or spend the 300 plus for a weber. Worst case is it cost you 25 bucks and you got to tinker with one.

Solex sucks . . . but only literally, read on

Originally Posted by RallyBob

Get the Weber.

The best Solex repair guy/tuner I know is Bill Daley. He can make them run like a good TAG watch. I used to ship him Solex carbs left and right. For every 10 or so carbs, maybe 2-3 were 'good ones'. The carbs warp in multiple places, and once they warp, they are junk. No rebuild kits will bring them back to life at that point, they are beyond repairing correctly.

However, every once in a while there's a 'good' Solex that shows up (I've only had one original Solex that did this personally) that actually performs correctly. The only other Solex I've owned that worked perfectly was an NOS Solex I had years ago...wish I had kept it. Otto has one that works very well on his Kadett, which is probably why he is emphatic about you keeping yours (we all love you Otto, but Solex did not earn their reputation by chance!).

That said, it's genuinely easier to keep and maintain a Weber than a Solex. It is far more tuneable in terms of parts availability and general knowhow, and you'll get a boost in power to boot. The frustration levels are dramatically reduced when dealing with a Weber too.

Bob

Absolutely right in all you say, Bob, and I concur with what you say from my personal experience, even as far as my Kadett's Solex is concerned. When I bought the car in Seattle and drove it back to Texas, it came with twin carbs . . . uh, a Weber 32/36 underhood, the original Solex and air cleaner in the trunk!

This car only had 26,800 original miles on it and is probably the best documented Kadett in existence, I mean, the original owner kept everything relating to ownership and maintenance of that car! Who else do you know who not only saves all annual registration renewal cards, but also removes and saves the annual license plate stickers! . . . and you thought I was anal!

But, back to carbs. When I got the car back to Texas and because everything else was original, I decided to go back to stock when I saw that the Solex still had its original metal carb ID tag! Going through the box full of paperwork I got with the car, I even discovered the original receipt for the Weber replacement carb . . . ring a bell, Bob?!

I thought it somewhat strange that the Solex was replaced without ever having been opened . . . almost always those carb ID tags get "lost" when they're first opened. This Solex is a vacuum secondary type and I quickly discovered the reason for its replacement . . . the most common vacuum Solex failure and which makes this carb completely untuneable, a ruptured vacuum diaphragm.

Had no trouble finding a replacement, since almost everyone thinks they're boat-anchors anyway and will gladly give you anything "Solex" just to be rid of it. I must say that this carb performs flawlessly in my only "A/T" Opel . . . end of story.

This car only had 26,800 original miles on it and is probably the best documented Kadett in existence,

Given your car's mileage and condition, I concur that a Solex is most befitting. In fact any truly original Opel or stock restored Opel should have the Solex if the intent is keeping it original for posterity or for the showfield.

But if you want to drive it regularly, I'd go with the Weber. My 'good' Solex in my 1974 Manta worked flawlessly when I got the car. In fact it would spin the 165/R13 radials with a little bit of brake-torquing (automatic trans). But, the day it 'popped' and stalled on me as I was trying to cross a busy intersection was the day I replaced it with a Weber...the Solex nearly cost me my life!

Wish I had kept that NOS mechanical secondary Solex though, that thing ran like a bear on my '70 Kadett Rallye.

This is an interesting thread, I'd start with tightening the obvious things down and then doing a rebuild if that doesn't work.

I've been thinking of replacing my original Solex on a 34K car since I got it simply because of the CFM numbers that Webers produce versus the Solex 32 DIDTA. I rebuilt a 32/36 and have it on standby for that. I'm also slowly building a new motor that will call for more air but I'm guessing Bob will tell you the rest of the plumbing has to be ready for that for different carbs to make sense.

But the three Mantas I owned 20-30 years ago all did well on the original Solex carb, as Otto attests. The worst condition was when the throats actually iced up in cold weather (Chicago) or slightly less cold high altitudes (Colorado). I've also met German Opelers who warn me not to go the Weber route and swear by the Solex.

My current Solex works works well and is not warped as far as I can tell, but the stacked manifold setup does cause it to boil over a bit in hot weather after you park it. It doesn't seem to be warping, but internal heat and pressure that causes fuel dump. It wants to flood - a bit - until you're back on the road and everything cools down and then you're fine again. A better fan setup might be the more obvious solution. There was a 1974 Opel service advisory for just this condition I could post if anyone is interested. If I could only find the replacement jets the advisory calls for...

Unlike Bob's example, my vacuum secondary is a little frustrating since it doesn't want to trip in the driveway but it seems to work on the road. Otto, I don't doubt you for a second.

To make the vacuum secondary kick in in the driveway, for testing that the diaphragm is in good condition, I always do the following.

From the engine bay, with the air-cleaner removed for clearance, I manually open the throttle to the point that the engine revs slightly above 3000rpms (which is the low end of the vacuum activation range). I keep the throttle there for a couple of seconds, then suddenly open it almost WOT and bring it back to approximately where it was. The sudden vacuum that will be created in the primary when bringing the throttle back, together with the throttle being open enough to allow secondary's linkage movement, will make the diaphragm activate briefly. And if the diaphragm is in good condition, you will see it's level slightly opening the secondary valve...

'74 Service Advisory

But the three Mantas I owned 20-30 years ago all did well on the original Solex carb, . . . I've also met German Opelers who warn me not to go the Weber route and swear by the Solex.

My current Solex works works well and is not warped . . . There was a 1974 Opel service advisory for just this condition I could post if anyone is interested. If I could only find the replacement jets the advisory calls for...

Unlike Bob's example, my vacuum secondary is a little frustrating since it doesn't want to trip in the driveway but it seems to work on the road. Otto, I don't doubt you for a second.

Bob, you are just six away........

Jim

Yes, do post that notice . . . uh, "the replacement jets", which ones and richer or leaner than original?

I don't know much about carbs, but I only have experience with the stock Solex carbs, the double barrel types [used on the high compression engines] are somewhat trickier than the single barrel [used on the low compression engines], and we [my brother & I] would change the double barrel for a single barrel Solex carb, doesn't make that much difference to us

Last edited by tekenaar; 07-09-2007 at 08:30 PM.
Reason: then - time (dan, toenmalig); than - comparative (dan, vergelijking)

CIH carbs - US vs. Euro

Originally Posted by 2 Fast 4 U

I don't know much about carbs, but I only have experience with the stock Solex carbs, the double barrel types [used on the high compression engines] are somewhat trickier than the single barrel [used on the low compression engines], and we [my brother & I] would change the double barrel for a single barrel Solex carb, doesn't make that much difference to us

Even though they are shown in some FSM illustrations here, NO US CIH engines were ever offered with a one-barrel Solex! All US CIH engines came with either a mechanical- (progressive) or vacuum- (load/RPM dependent) secondary two-barrel Solex . . . period.

One barrel Solexes of various sizes and numbers were strictly used on the 1.1 OHV from 1966-on and at the same time that electrical systems were changed from 6V to 12V. All the 6V Opel models sold here from 1958-62 (Rekord PII, 1.5/1.7 OHV) and from 1964-65 (Kadett, 1.0 OHV) used a single one-barrel Carter carb . . .

Could be that 2 fast is looking at things backwards and sees the "double barrel" Solex as the twin-carb 1.1 setup and the single as the single 2-barrel didta on the 1.9s.

I am looking for that service advisory, I have a few stacks lying around. It's possible that remember it from one of Mach One Tom's collection, he has the best set I know of. I'm pretty sure it was a part number bulletin that did not specify diameters.

Probably 1/3 of all Opel service advisories dealt with the Solex. There are too many to attach here but one interesting bulletin corrected the specs in the 1974 factory service manual. I am trying to upload it but my scan distorts the page badly so far.